The present invention relates to improvements in levels, also called spirit levels, and more particularly to improvements in spirit levels (hereinafter called levels for short) of the type wherein at least one pointer is movable back and forth longitudinally of a housing which carries one or more so-called bubble tubes, and wherein the housing carries a scale which indicates the position of the pointer relative to the housing and hence the orientation of the narrow sidewalls of the housing relative to a horizontal or vertical plane.
As a rule, or in many instances, the housing of a level (such housing can be made of wood, metal or a plastic material) has a polygonal cross-sectional outline and carries one or more bubble tubes which enable the user to ascertain or to select the inclination of a surface or part relative to the horizontal and/or relative to the vertical.
Published French patent application Serial No. 2 602 044 discloses a level wherein the narrow top wall of the housing is provided with a longitudinally extending inverted T-shaped groove slidably receiving portions of two discrete followers. Each follower carries a stylus or another suitable marking tool which extends at right angles to the directions of movement of the respective follower and can be utilized to apply indicia to the surface of a part which is adjacent the top wall of the housing. Clamping devices are provided to individually secure the followers in selected positions relative to the housing of the instrument. The clamping devices have portions engageable by the working end of a screwdriver or another suitable tool which is used to fix the respective pointer in a given position relative to the housing, or to disengage the pointer preparatory Lila to shifting to a different position relative to the housing.
A drawback of the just described proposal is that the followers are located outside of the housing and thus occupy additional space. Moreover, such exposed followers are likely to be damaged or accidentally shifted relative to the housing, and the external groove is likely to gather impurities (e.g., at a construction site and/or in a shop).
Published German patent application Serial No. DE 197 49 026 A1 discloses a level wherein a housing having a polygonal cross-sectional outline carries several followers each of which surrounds three outer sides of the housing. Each follower has at least one pointer and a passage for a stylus at a level above the top wall as well as at a level below the underside of the housing.
A drawback of the just described level (and such drawback is shared by the level disclosed in the afore-discussed French patent application) is that at least one of the followers extends outwardly beyond at least one narrow sidewall of the housing. This interferes with the customary manipulation and utilization of the level. For example, a level of the type disclosed in the afore-discussed published French or German patent application cannot be placed from below against the underside of a ceiling and/or from above against the upper side of a wall or the like. This greatly reduces the versatility and popularity of such levels.
An object of the present invention is to provide a spirit level which exhibits the advantages but does not embody the drawbacks of the aforediscussed conventional levels.
Another object of the invention is to provide a level which can be manipulated as readily as a standard level but further exhibits advantages, such as convenience of handling, not exhibited by conventional levels.
A further object of the invention is to provide a novel and improved housing for use in the improved level.
An additional object of the instant invention is to provide a novel and improved housing-follower combination for use in the above outlined improved level.
Still another object of this invention is to provide a level wherein the housing as well as each follower can stand pronounced deforming stresses and which can be assembled of simple mass-produced parts at a reasonable cost.
A further object of the invention is to provide a novel and improved method of simplifying the assembly of the housing with the other parts of the improved level.
Another object of the present invention is to provide a level which can be utilized to apply marks to selected portions of pieces of furniture and/or other parts with a high degree of accuracy, which can be readily manipulated by workmen upon a minimum of training, and which can be designed to accept and to accurately locate any selected practical stylus or other marking tool.
An additional object of the invention is to provide a level which can be assembled or taken apart in a simple and time-saving manner.
The invention is embodied in a spirit level which comprises a housing having at least one wall (such as a relatively wide front wall) provided with an elongated slot, at least one mobile follower which includes a first portion disposed in the housing and a second portion which is outwardly adjacent the wall and is slidable in the slot to move the first portion within the housing, and at least one bubble tube provided in the housing.
It is presently preferred to employ a housing having a polygonal (preferably square and most preferably rectangular) cross-sectional outline.
The first portion of the at least one follower preferably constitutes its major portion.
A second wall of the housing (this second wall is preferably positioned in such a way that it is spaced apart from the at least one wall) can be provided with at least one second slot which is aligned with the elongated slot of the at least one wall. The at least one follower is or can be provided with a passage (such as a bore or a hole) having a first end which is accessible from the outside at the at least one wall, and a second end which is accessible from the outside at the second wall. Such passage can receive a stylus or another marking tool which can be moved by the at least one follower or which can move the at least one follower relative to the housing to a desired position in which the marker is to apply a suitable indicium to a surface of a wall, to a piece of furniture, or the like.
As a rule, the second portion of the at least one follower is provided with one or more pointers which is or which are outwardly adjacent the slot in the at least one wall. The outer side of such at least one wall can be provided with one or more suitably graduated scales to facilitate accurate positioning of one or more pointers relative to the housing and to thus facilitate accurate positioning of the marker or markers relative to the object or surface which is adjacent the second end(s) of the passage(s) defined by the follower.
The at least one wall can be provided with two elongated marginal portions which flank the slot in the at least one wall and serve as guide rails for that part of the second portion of the at least one follower which extends through the elongated slot. Such second portion of the at least one follower can be provided with two pointers each of which is adjacent one of the two marginal portions. At least one such marginal portion can be provided with a scale for the respective pointer of the at least one follower.
If the housing includes a second wall which is spaced apart from and confronts the at least one wall, the first portion of the at least one follower can include at least one extension which abuts and tracks the second wall during movement of the at least one follower relative to the housing. The at least one extension can include one or more ribs which abuts or abut the inner side of the second wall.
The housing can be provided with at least one internal guide which extends longitudinally of the elongated slot, and the first portion of the at least one follower can include at Least one part which tracks the internal guide during movement of the at least one follower relative to the housing. Such housing can further comprise the aforementioned second wall which is spaced apart from and confronts the at least one wall, as well as two spaced-apart sidewalls which connect the at least one wall with the second wall. The at least one internal guide can be provided on one of the sidewalls, and such internal guide can include an elongated rail; the at least one part of the first portion of the at least one follower is or can be arranged to slide along the rail.
The housing can further comprise at least one reinforcing portion which is at least substantially parallel to the at least one slot, and the at least one internal guide can be provided on such reinforcing portion. For example, the reinforcing portion can include a tube which can have a polygonal cross-sectional outline.
It is also possible to assemble the housing of two discrete sections which extend lengthwise of the slot; the at least one internal guide can form part of one of these sections.
For example, the housing can comprise two discrete elongated sections which flank the slot, and two caps or analogous end portions which connect the respective end portions of the two sections to each other. The first end portion of the at least one follower can be provided with at least one corrugated reinforcing portion which is slidably recessed into the external surface of the at least one wall of the housing.
The improved level can comprise a plurality of discrete mobile followers each of which includes a first portion disposed in the housing and a second portion outwardly adjacent the at least one wall and slidable in the elongated slot of such wall to move the first portion of the respective follower within the housing.
Each of the aforementioned cupped or otherwise configurated end pieces of the housing can serve as a receptacle or support for a discrete bubble tube.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved level itself, however, both as to its construction and the modes of assembling and utilizing the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.